#pragma GCC optimize("Ofast") #pragma GCC target("avx2") char*mmap(); #define rd(v) int v=0;{int _c;while(_c=*rp++-48,_c>=0)v=v*10+_c;} #define wt_rev(v) {long _z=v;do*--wp=_z%10+48;while(_z/=10);} unsigned long vis[50000000/64+2]; main(){ char*rp=mmap(0l,1l<<25,1,2,0,0ll); rd(n); long res=0; for(long i=1;i<=n;++i){ if(!(vis[i>>6]&1ul<>6]|=1ul<