#pragma GCC optimize("Ofast") #pragma GCC target("avx2") #define rd_skip() while(*rp++>=48) #define rd(v) int v=0;{int _c;while(_c=*rp++-48,_c>=0)v=v*10+_c;} char wbuf[1<<25]; #define WTHI(v) {long _z=v,_n=0,_d=0;while(++_n,_d=_d<<8|0x30|_z%10,_z/=10);*(long*)wp=_d;wp+=_n;} #define WTLO(v) {long _z=v,_n=8,_d=0;while(_d=_d<<8|0x30|_z%10,_z/=10,--_n);*(long*)wp=_d;wp+=8;} #define wt(v) WTHI(v) int count[301]; int total; typedef struct { int a[10]; } Bits; Bits dp[200000]; main(){ char rbuf[64]; read(0,rbuf,sizeof rbuf); char*rp=rbuf; rd(n); rd(m); for(int i=1;i<=n;++i){ for(int j=1;j<=n;++j){ int p=!__builtin_parity(i*j); count[i]+=p; total+=p; } } if((total^m)&1 || m>total){ write(1,"-1\n",3); _exit(0); } m=total-m>>1; for(int k=1;k<=m;++k){ dp[k].a[9]=-1; } for(int i=1;i<=n;++i){ for(int k=m;k>=count[i];--k){ Bits b=dp[k-count[i]]; if(b.a[9]>=0){ b.a[i>>5]|=1<>5]&1<>5]&1<