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

int main(void) {
	double a, b, c;

	printf("input length1: ");
	scanf("%lf", &a);
	printf("input length2: ");
	scanf("%lf", &b);
	c = sqrt(a * a + b * b);
	printf("length3 is: %f\n", c);
	return 0;
}