#include<bits/stdc++.h>
using namespace std;
#define all(vec) vec.begin(),vec.end()
typedef long long int ll;
typedef pair<ll,ll> P;
const ll MOD=1000000007;
const ll INF=1000000010;
const ll LINF=4000000000000000010LL;
const int MAX=310;
const double EPS=1e-3;
int dx[4]={0,1,0,1};
int dy[4]={0,0,1,1};
int main(){
    ll a,b,t;cin>>a>>b>>t;ll c=a*(t/a);if(t>c||c==0)c+=a;
	ll aa=c/a;
	ll ans=c;
	for(int i=0;i<=10000000;i++){
		c+=b;
		aa-=(c-t)/a;if(aa<0)break;
		c-=a*((c-t)/a);
		ans=min(c,ans);
	}
	cout<<ans<<endl;
    return 0;
}