#include<bits/stdc++.h>
using namespace std;
int main()
{
	int a[11000],b[11000],c[11000],la,lb,lc,i;
	char d[11000],e[11000],f[11000];
	memset(a,0,sizeof(a));
	memset(b,0,sizeof(b));
	memset(c,0,sizeof(c));
	cin>>d>>e;
	if(strlen(d)<strlen(e)||(strlen(d)==strlen(e)&&strcmp(d,e)<0)){
		strcpy(d,e);
		strcpy(e,f);
		strcpy(f,d);
		printf("-");
	}
	la=strlen(d);
	lb=strlen(e);
	for(int i=0;i<=la-1;i++){
		a[la-i]=int(d[i]-'0');
	}
	for(int i=0;i<=lb-1;i++){
			b[lb-i]=int(e[i]-'0');
		}
		i=1;
		while(i<=la||i<=lb){
			if(a[i]<b[i]){
				a[i]+=10;a[i+1]--;
			}c[i]=a[i]-b[i];
			i++;
		}
		lc=i;
		while((c[lc]==0)&&(lc>1)){
			lc--;
		}
		for(int i=lc;i>=1;i--){
			cout<<c[i];
		}
	return 0;
}