#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#define ll long long
using namespace std;
const int maxn=10010;

int i,j,n,k,cnt;
int a[maxn];
ll m;

void work2(int a){
    if(a&1)a++;
    a>>=1;
    for(int i=1;i<=a;i++)printf("4");
    for(int i=1;i<=a;i++)printf("7");
    printf("\n");
}
void work1(int a,int *A){
    if(a&1){work2(a);return;}
    int j=0;
    for(int i=a;i;i--)if(A[i]==4)j++;
    if(j<(a>>1)){work2(a+1);return;}
    int i=1;
    while(j>(a>>1)){
        j--;
        while(A[i]==7)i++;
        A[i]=7;
    }
    for(i=a;i;i--)printf("%d",A[i]);printf("\n");
}

int main(){
//    freopen("uva.in","r",stdin);
    
    scanf("%d",&n);
    for(int kk=1;kk<=n;kk++){
        scanf("%I64d",&m);
        if(m==0){
            printf("47\n");
            continue;
        }
        j=0;
        while(m){
            a[++j]=m%10;
            m/=10;
        }
        int jj=j;
        while(jj&&(a[jj]==7||a[jj]==4))jj--;
        if(!jj)work1(j,a);
        else if(a[jj]<4){
            for(int jjj=jj;jjj;jjj--)a[jjj]=4;
            work1(j,a);
        }else if(a[jj]>7){
            bool flag=false;
            for(int jjj=j;jjj>jj;jjj--)if(a[jjj]==4)flag=true;
            if(flag){
                int jjj=jj+1;
                while(a[jjj]!=4)jjj++;
                a[jjj--]=7;
                while(jjj)a[jjj--]=4;
                work1(j,a);
            }else{
                work2(j+1);
            }
        }else{
            a[jj]=7;
            for(int jjj=jj-1;jjj;jjj--)a[jjj]=4;
            work1(j,a);
        }
    }
    
    return 0;
}