Best reward from 3 rolls using Monte Carlo Experiment

MaxFrom3Rolls.py

"""Licensed under GPLv3 <http://www.gnu.org/licenses/>.
Authors:
Eric Lopes
"""
import random
def roll(x=[6,6]):
    for i in range(2):
        v=random.randint(1,6)
        if v>=x[i]: return v
    v=random.randint(1,6)
    return v

def monteCarlo(n=1000, x=[6,6]):
    c=0
    for i in range(n):
        c+=roll(x)
    return c/n

def testAll(n=10**6):
    c=0
    mt = [[0 for a in range(6)] for b in range(6)]
    for i in range(1,7):
        for j in range(1,7):
            v=monteCarlo(n,[i,j])
            mt[i-1][j-1]=v
            if v>c:
                c=v
                print(i,j,v)
    return mt

testAll(10**6)