#include<bits/stdc++.h> using namespace std; char a[10087],b[10087]; int a1[10087],b1[10087],c[10087]; int main() { cin>>a>>b; int l1=strlen(a); int l2=strlen(b); for(int i=0;i<max(l1,l2);i++){ if(i<l1){ a1[i]=a[l1-i-1]-'0'; } else{ a1[i]=0; } if(i<l2){ b1[i]=b[l2-i-1]-'0'; } else{ b1[i]=0; } } int x=0; int l3=0; for(int i=0;i<max(l1,l2);i++){ l3++; b1[i]+=x; if(a1[i]>=b1[i]){ c[i]=a1[i]-b1[i]; x=0; } else{ c[i]=(a1[i]-b1[i])%10; if(c[i]!=0){ x=(b1[i]-a1[i])/10+1; } else{ x=(b1[i]-a1[i])/10; } } } for(int i=0;i<l3;i++){ cout<<c[l3-1-i]; } return 0; }