#include <iostream>#include <cstring>using namespace std;int main(){char input[21],temp[21],num[21];long n,sum[2],i,j,dif;while(cin>>input){strcpy(temp,input);n=strlen(input)/2;sum[0]=sum[1]=0;for(i=0;i<n;i++) sum[0]+=input[i]-'0';j=2*n;for(;i<j;i++) sum[1]+=input[i]-'0';i=2*n-1;while(sum[1]>sum[0]){sum[1]-=temp[i]-'0';temp[i]='0';j=i-1;while(temp[j]=='9'&&j>=n){sum[1]-=9;temp[j]='0';j--;}if(j==n-1){while(temp[j]=='9'){sum[0]-=9;temp[j]='0';j--;}temp[j]+=1;sum[0]++;}else{temp[j]+=1;sum[1]++;}i--;}dif=sum[0]-sum[1];i=2*n-1;while(1){if('9'-temp[i]>=dif){temp[i]+=dif;break;}else{dif-='9'-temp[i];temp[i]='9';}i--;}for(i=0;i<20;i++) num[i]='0';long carry(0);for(i=2*n-1;i>=0;i--){j=temp[i]-carry-input[i];if(j<0){num[i]=10+j+'0';carry=1;}else{num[i]=j+'0';carry=0;}}j=2*n;for(i=0;i<j-1;i++){if(num[i]!='0') break;}for(;i<j;i++) cout<<num[i];cout<<endl;}return 0;}
