#include<bits/stdc++.h>
using namespace std;
int main()
{
int a[256],b[256],c[256],lena,lenb,lenc,i;
char n[256],n1[256],n2[256];
memset(a,0,sizeof(a));
memset(b,0,sizeof(b));
memset(c,0,sizeof(c));
gets(n1);
gets(n2);
if(strlen(n1)<strlen(n2)||(strlen(n1)==strlen(n2)&&strcmp(n1,n2)<0))
{
strcpy(n,n1);
strcpy(n1,n2);
strcpy(n2,n);
cout<<"-";
}
lena=strlen(n1);
lenb=strlen(n2);
for(i=0;i<=lena-1;i++)
a[lena-i]=int(n1[i]-'0');
for(i=0;i<=lenb-1;i++)
b[lenb-i]=int(n2[i]-'0');
i=1;
while(i<=lena||i<=lenb)
{
if(a[i]<b[i])
{
a[i]+=10;
a[i+1]--;
}
c[i]=a[i]-b[i];
i++;
}
lenc=i;
while((c[lenc]==0)&&(lenc>1))lenc--;
for(i=lenc;i>=1;i--)cout<<c[i];
cout<<endl;
return 0;
}
