# your code goes here
a = "quan tri mang cham com"
i = len(a)
while (i > 0):
i = i - 1
if a[i] == "a":
print(i)
break
IyB5b3VyIGNvZGUgZ29lcyBoZXJlCmEgPSAicXVhbiB0cmkgbWFuZyBjaGFtIGNvbSIKaSA9IGxlbihhKQp3aGlsZSAoaSA+IDApOgogaSA9IGkgLSAxCiBpZiBhW2ldID09ICJhIjoKICBwcmludChpKQogIGJyZWFrCgo=