#include<bits/stdc++.h>
using namespace std;
long long n,ans,a,b,t,mc,m,j,q;
int main()
{
cin>>a>>b>>n;
q=n;
mc=a*5+b*2;
m=n/mc;
q-=mc*m;
for(int i=1;i<=7;i++)
{
if(q<=0) break;
if(i<=5) q-=a;
else q-=b;
j++;
}
cout<<m*7+j;
}