'use strict'

function main(input){
  const lines = input.split('\n');
  const S = lines[0];
  const T = lines[1];

  let tIndex = undefined;
  for(let i=0;i<S.length-T.length+1;i++){
    let same_count=0;
    for(let j=0;j<T.length;j++){
      let partS = S.slice(i,i+T.length).split('');
      let partT = T.split('');
      if(partS[j]=='?' || partS[j]==partT[j]){
        same_count++;
      }
    }
    if(same_count==T.length){
      tIndex=i;
      break;
    }
  }

//  console.log(tIndex);

  if(tIndex+T.length>S.length || tIndex==undefined){
    console.log('UNRESTORABLE');
    return;
  }

  let result =[];

  for(let i =0;i<S.length;i++){
    if(i>=tIndex && i < tIndex+T.length){
      result.push(T[i-tIndex]);
    }else{
      if(S[i]=='?'){
        result.push('a');
      }else{
        result.push(S[i]);
      }
    }
  }
  console.log(result.join(''));
}

main( require('fs').readFileSync('/dev/stdin','utf8') )