#include<stdio.h>
int main(){
    int N;
    scanf("%d",&N);
    if(N<1){
        printf("Invalid input\n");
        return 0;
    }
    int ids[100];
    int duplicate[100];
    int dupcount=0;
    for(int i=0;i<N;i++){
        scanf("%d",&ids[i]);
    }
    for(int i=0;i<N;i++){
        for(int j=0;j<N;j++){
            if(ids[i]==ids[j]){
                int alreadyFound=0;
                for(int k=0;k< dupCount;k++){
                    
                
            }
            if(duplicates[k]==ids[i]){
                alreadyFound=1;
                break;
            }
        }
        if(!alreadyFound){
            duplicate[dupCount++]=ids[i];
        }
    }
}
if(dupCount==0){
    printf("No duplicates found\n");
}else{
    for(int i=0;i<dupCOunt;i++){
        printf("%d",duplicates[i]);
    }
}
return 0;
}
    }
}
}