#include <stdio.h>
#include <errno.h>
#include <string.h>

double yval(double a, double b) {
    return a * a - 1.0 / (1.0 + b * b);
}


int main(void)
{
    FILE *fin = NULL;
    FILE *fout = NULL;
    double a, b;
    double y;

    /* --- 入力ファイルオープン --- */
    fin = fopen("input.in", "r");
    if (fin == NULL) {
        fprintf(stderr, "Error: cannot open input.in: %s\n", strerror(errno));
        return 1;
    }

    /* --- a の読み込み --- */
    if (fscanf(fin, "%lf", &a) != 1) {
        fprintf(stderr, "Error: failed to read parameter a from input.in\n");
        fclose(fin);
        return 1;
    }

    /* --- b の読み込み --- */
    if (fscanf(fin, "%lf", &b) != 1) {
        fprintf(stderr, "Error: failed to read parameter b from input.in\n");
        fclose(fin);
        return 1;
    }

    fclose(fin);

    /* --- 計算 --- */
    y = yval(a, b);

    /* --- 出力ファイルオープン --- */
    fout = fopen("input.out", "w");
    if (fout == NULL) {
        fprintf(stderr, "Error: cannot open input.out: %s\n", strerror(errno));
        return 1;
    }

    /* --- 書き込み --- */
    if (fprintf(fout, "%.17g\n", y) < 0) {
        fprintf(stderr, "Error: failed to write to input.out\n");
        fclose(fout);
        return 1;
    }

    /* --- クローズチェック --- */
    if (fclose(fout) != 0) {
        fprintf(stderr, "Error: failed to close input.out: %s\n", strerror(errno));
        return 1;
    }

    return 0;
}