#include <cstdio>
#include <cmath>

#define FOR( i, l, r) for(int i = (l)    ; i <  (r); i++)
#define FOR1(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define REV( i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define REV1(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define INC( i, n) FOR( i, 0, n)
#define INC1(i, n) FOR1(i, 1, n)
#define DEC( i, n) REV( i, 0, n)
#define DEC1(i, n) REV1(i, 1, n)

typedef long long   signed int LL;
typedef long long unsigned int LU;

// ---- ----

template<typename T> void swap(T& x, T& y) { T t = x; x = y; y = t; return; }

int main() {
	int a, b;
	scanf("%d%d", &a, &b);
	if(a != b) {
		if(a < b) { swap(a, b); }
		printf("%f\n", std::sqrt(a * a - b * b));
	} else {
		printf("%f\n", a * std::sqrt(2));
	}
	
	return 0;
}