A = input()
P = map(lambda x:float((100-int(x))/100.0), raw_input().split())
T = [[0 for _ in xrange(16)] for _ in xrange(A, 81)]
for i in xrange(1, 15):
    T[0][i] = 1.0

for i in xrange(1, 81-A):
    for j in xrange(1,15):
        T[i][j] = ((1-T[i-1][j-1]) * (1-T[i-1][j+1]) * P[0] + \
                  (1-T[i-1][j-1]) * T[i-1][j+1] * P[1] + \
                  T[i-1][j-1] * (1-T[i-1][j+1]) * P[1] + \
                  T[i-1][j-1] * T[i-1][j+1] * P[2]) * \
                  T[i-1][j]
    #for i in xrange(81-A):
    #    print map(lambda x:'%.4f'%x, T[i])
    #print
#print map(float, T[-1])
print '%.6f'%(sum(T[-1])*2)