AAAAARY3gbRofgWWcrSmopM6U7p3XbJo2ytTGOoFIeN2Em1wQ4Gdj1cl9V5SEOOmFXnNyOJyXqfqh7V7ZrUmDBV/BEAvqlE2S9m2F4PqpzuOBFeONVIoLMAzgLfWEQ7LXqDynjGWoYujt9xxAXRUWN4P2HDV2b2juWoFQIImIYLHXYMPgorLY1t7vPNpHrIYYeUetX/UM3zJSgfhIQcMRrPHPBXRcT1IBlbUDT0X0fONtq9IXMZ40xYEutL8fRB0S4PWG0GpqMEyLs1IXzHemsAgLTskx7Ncte+pi/ydLb9wxesqH/80B1UDaQBn2lLxTGst8kbmqaDV+altcysxq5URo58ejs33G8rb2+qICAIaPyybYxthYxudf6tY42enkdBNguaEGUeeOSnV+8Ec7Coc0ICwDv8w+lay2aaWF3tTcPX3mAsSpvsMXOLKo6LOHpKX3dA3ZHoeg8LFwI0gBQwCr0E=

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

#include<bits/stdc++.h>
#pragma GCC optimize(3,"Ofast","inline")
using namespace std;
typedef long long ll;
ll p1=4,p2=4,a1,a2,r,d1,d2,z,s1,s2,x,zz;
	int getRand(int min, int max) {
	return (rand() % (max - min + 1)) + min;
}
int main(){
	p1=p2=1;
	p1=10;
	p2=10;
	z=0;
	while(1){

		z++;
		x++;
		zz++;
		cout<<"!!!!!!!!!!!!!!!第"<<x<<"回合!!!!!!!!!!!!!!!!"<<endl;
			if(z==3){
				cout<<endl<<"###############分发放大镜###############" <<endl ;
				d1++;
				d2++;
				z=0;
			}
		srand(time(0));
		cout<<"--------------------P1的回合--------------------"<<endl<<endl;
		cout<<"P1 HP:"<<p1<<endl;
		cout<<"p1 放大镜:"<<d1<<endl<<endl;
		while(1){
			r=getRand(0,1);
			if(d1>0){
				cout<<"是否使用放大镜"<<endl<<endl<<"1:是   2:否"<<endl;
				cin>>s1;
				if(s1==1){
					d1--;
					if(r==1){
						cout<<"下一发子弹是（实弹）"<<endl<<endl;
					}
					else{
						cout<<"下一发子弹是（空弹）"<<endl<<endl;
					}
				}
			}
		cout<<"打自己还是打别人"<<endl<<endl;
		cout<<"1:打别人   2:打自己"<<endl;
		cin>>a1;
		if(a1==1){
			if(r==1){
				p2--;
				cout<<"P2 HP-1"<<endl;
			}
			else {
				break;
			}
		}
		else if(a1==2){
			if(r==1){
				p1--;
				cout<<"P1 HP-1"<<endl;
				break;
			}
			else{
				p1++;
				cout<<"P1 HP+1"<<endl;
			}
		}
		
		}system("cls");
		cout<<"--------------------P2的回合--------------------"<<endl<<endl ;
		cout<<"P2"<<" HP:"<<p2<<endl;
		cout<<"p2 放大镜:"<<d2<<endl<<endl;
		while(1){
			r=getRand(0,1);
			if(d2>0){
				cout<<"是否使用放大镜"<<endl<<endl<<"1:是   2:否"<<endl;
				cin>>s2;
				if(s2==1){
					d2--;
					if(r==1){
						cout<<"下一发子弹是（实弹）"<<endl<<endl;
					}
					else{
						cout<<"下一发子弹是（空弹）"<<endl<<endl;
					}
				}
			}
			cout<<"打自己还是打别人"<<endl<<endl;
			cout<<"1:打别人   2:打自己"<<endl;
			cin>>a1;
			if(a1==1){
				if(r==1){
					p1--;
					cout<<"P1 HP-1"<<endl;
				}
				else break;
			}
			else if(a1==2){
				if(r==1){
					p2--;
					cout<<"P2 HP-1"<<endl;
					break;
				}
				else{
					p2++;
					cout<<"P2 HP+1"<<endl;
				}
			}
				
		}system("cls");
			if(p2<=0){
				cout<<"P1赢了";
				return 0;
			}
			if(p1<=0){
				cout<<"P2赢了";
				return 0;
			}
		}
		return 0;
	}

#include <iostream>
#include <cstring>
#include <climits>
using namespace std;

const int MAXN = 205;        
const long long INF = 1e18;   

long long dist[MAXN][MAXN]; 

int main() {

    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int N, M, Q;
    cin >> N >> M >> Q;
    

    for (int i = 1; i <= N; ++i) {
        for (int j = 1; j <= N; ++j) {
            if (i == j) {
                dist[i][j] = 0;
            } else {
                dist[i][j] = INF;
            }
        }
    }
    

    for (int i = 0; i < M; ++i) {
        int u, v, w;
        cin >> u >> v >> w;

        if (w < dist[u][v]) {
            dist[u][v] = w;
        }
    }
    

    for (int k = 1; k <= N; ++k) {         
        for (int i = 1; i <= N; ++i) {      
            for (int j = 1; j <= N; ++j) {  

                if (dist[i][k] != INF && dist[k][j] != INF) {
                    if (dist[i][j] > dist[i][k] + dist[k][j]) {
                        dist[i][j] = dist[i][k] + dist[k][j];
                    }
                }
            }
        }
    }
    

    for (int i = 0; i < Q; ++i) {
        int S, T;
        cin >> S >> T;
        if (dist[S][T] == INF) {
            cout << "impossible" << endl;
        } else {
            cout << dist[S][T] << endl;
        }
    }
    
    return 0;
}