#include <stdio.h>
int main(){
	long long a,b,c,r,s;
	scanf("%lld%lld%lld",&a,&b,&c);
	for(s=0;s<c;s+=a);
	r=s;
	for(;s%b;){
		for(s-=a;s<c;s+=b);
		if(r>s)r=s;
	}
	printf("%lld\n",r);
	return 0;
}