//acmp.ru 0755 sbor_zemlyaniki.cpp 6%

#include <stdio.h>

int main(){
	freopen("INPUT.TXT", "r", stdin);
	freopen("OUTPUT.TXT", "w", stdout);

	short x, y, z;
	scanf("%hi%hi%hi", &x, &y, &z);

	if(z > x + y){
		printf("Impossible");
	}else {
		printf("%hi", (x+y)-z);
	}
}