#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] != 0 ){
		return memo[left];
	}
	int min_A = solve( left - A );
	int min_B = solve( left - B );
	memo[left] = min( min_A, min_B );
	return memo[left];
}

int main( void ){
	int i;
	scanf("%d %d %d",&A,&B,&T);
	int min_left = MAX_T;
	for(i=0;i*B<T || i>A;i++){
		int pay = B * i + ( A * ( (T-B*i-1)/A + 1 ) );
		int left = pay - T;
		min_left = min( min_left, left );
		if( min_left == 0 ){ break; }
		//printf("pay:%d left:%d min:%d\n",pay,left,min_left);
	}
	printf("%d\n",min_left + T );
	
	
	return 0;
}