from math import sqrt, cos, sin

a, b = map(float, input().split())
f = 'abs(' + input().replace('^', '**') + ')'

N = 2000
coef = (b - a) / (2 * N)

def func_i(i):
    x = a + i * coef
    return eval(f)

ans = func_i(0)

for i in range(1, 2 * N + 1, 2):
    ans += 4 * func_i(i)
for i in range(2, 2 * N + 1, 2):
    ans += 2 * func_i(i)

print(ans * coef / 3)