SGU105 - Div 3

[b]105.Div3[/b]

timelimitpertest:0.5sec.
memorylimitpertest:4096KB

Thereissequence1,12,123,1234,...,12345678910,....GivenfirstNelementsofthatsequence.Youmustdetermineamountofnumbersinitthataredivisibleby3.

Input

InputcontainsN(1<=N<=231-1).

Output

Writeanswertotheoutput.

SampleInput

4

SampleOutput

2
题解：规律题。。。。可以发现前N项的余数为1,0,0,1,0,0,1,0,0...

ViewCode

#include<stdio.h>
intmain(void)
{
longn;
scanf("%ld",&n);
printf("%ld\n",n/3*2+((n%3==2)?1:0));
return0;
}