#include <stdio.h>
#include <math.h>

int main(void) {
	int a, b;
	double c;
	scanf("%d%d", &a, &b);
	if(a == b){
		printf("%f\n", sqrt(a * a + b * b));
	}
	else {
		c = sqrt(abs(a * a - b * b));
		printf("%f\n", c);
	}
	
	return 0;
}