#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

#define rd_init() char*rp=({char*mmap();mmap(0l,1l<<25,1,2,0,0ll);})
#define rd() ({long _v=0,_c;while(_c=*rp++-48,_c>=0)_v=_v*10+_c;_v;})
#define rep(v,e) for(typeof(e)v=0;v<e;++v)

char wbuf[1<<25];
long a[300002];

int main(){
	char*wp=wbuf;
	rd_init();
	long n=rd();
	long k=rd()-1;
	long s=0;
	a[n]=1;
	long i;
	for(i=n;i--;){
		if(rp[i]=='0'){
			a[i]=0;
		}else if(rp[i]=='1'||rp[i]=='2'&&rp[i+1]<='6'){
			a[i]=a[i+1]+a[i+2];
			if(a[i]>k){
				break;
			}
		}else{
			a[i]=a[i+1];
		}
	}
	rep(j,n){
		int b=(rp[j+1]=='0'||j>=i&&k>=a[j+1]&&(k-=a[j+1],1))?(rp[j++]-'0')*10:0;
		*wp++=b+rp[j]+('a'-'1');
	}
	write(1,wbuf,wp-wbuf);
	_exit(0);
}