def main():
    import sys
    input = sys.stdin.read().split()
    N = int(input[0])
    p = float(input[1])
    q = float(input[2])
    
    if q == 0.0:
        print("{0:.15f}".format(p))
        return
    
    a = [0.0] * (N + 1)
    b = [0.0] * (N + 1)
    
    a[0] = 1.0
    a[1] = 0.0
    b[0] = 0.0
    b[1] = 1.0
    
    for i in range(2, N + 1):
        a[i] = (a[i-1] - p * a[i-2]) / q
        b[i] = (b[i-1] - p * b[i-2]) / q
    
    numerator = p * a[N-1] - a[N]
    denominator = b[N] - p * b[N-1]
    
    if denominator == 0:
        x = 0.0
    else:
        x = numerator / denominator
    
    print("{0:.15f}".format(x))
    
if __name__ == "__main__":
    main()