Improve iostream with stdio unsync: real    0m1.029s -> 0m1.020s user    0m0.538s -> 0m0.569s sys     0m0.311s -> 0m0.262s refs:   148,846,05 -> 53,570,098
Improve iostream with stdio unsync:
real    0m1.029s -> 0m1.020s
user    0m0.538s -> 0m0.569s
sys     0m0.311s -> 0m0.262s
refs:   148,846,05 -> 53,570,098

bepec/challenge,bepec/challenge,bepec/challenge,bepec/challenge