#include <stdio.h>
#include <stdlib.h>

#define MAX_T 1000000001
int memo[MAX_T];
int A,B,T;
#define min(a,b) (((a)>(b))?(b):(a))

int solve( int left){
	
	if( left <= 0 ){
		return -left;
	}
	
	if( memo[left] != -1 ){
		return memo[left];
	}
	
	memo[left] = min( solve( left - A ), solve( left-B) );
	return memo[left];
}

int main( void ){
	int i;
	scanf("%d %d %d",&A,&B,&T);
	for(i=0;i<T+1;i++){ memo[i] = -1; }
	
	printf("%d\n",solve(T)+T);
	return 0;
}