g=lambda x,o,i=1:x<10and[x,i]or g(eval(o.join(`x`)),o,i+1)
f=lambda a,o,b:g(eval('%s'*3%(a,o,b)),o)
for x in [[81, '+', 31],
[351, '+', 14568],
[21, '*', 111],
[136, '*', 2356]]:
print('%-17s -> %s'%(x,f(*x)))
Zz1sYW1iZGEgeCxvLGk9MTp4PDEwYW5kW3gsaV1vciBnKGV2YWwoby5qb2luKGB4YCkpLG8saSsxKQpmPWxhbWJkYSBhLG8sYjpnKGV2YWwoJyVzJyozJShhLG8sYikpLG8pCgpmb3IgeCBpbiBbWzgxLCAnKycsIDMxXSwKICAgICAgICAgIFszNTEsICcrJywgMTQ1NjhdLAogICAgICAgICAgWzIxLCAnKicsIDExMV0sCiAgICAgICAgICBbMTM2LCAnKicsIDIzNTZdXToKICAgIHByaW50KCclLTE3cyAtPiAlcyclKHgsZigqeCkpKQ==
[81, '+', 31] -> [4, 2]
[351, '+', 14568] -> [6, 3]
[21, '*', 111] -> [8, 3]
[136, '*', 2356] -> [0, 2]