Bulgarian Solitaire

const N = parseInt(readline());
var inputs = readline().split(' ');
let supZero = 0;
let arrayTemp = [];
let search = true;


while ( search ){

    inputs = down(inputs);

    for (let index = 0; index < arrayTemp.length; index++) {

        if ( inputs.filter(x => x !=0).sort().join('') === arrayTemp[index].filter(x => x != 0 ).sort().join('')){
            search = false;
            console.log(arrayTemp.length - index);
            break;
        }

    }

    arrayTemp.push(inputs.filter(x => x !=0));

    if ( arrayTemp.length > 100){
        arrayTemp = [];
    }


}


function down(arr){
    arr.map(function(value,i){
        if ( value != 0 ){
            arr[i] = value - 1 ;
            supZero++;
        }
    })
    arr.push(supZero);
    supZero = 0;
    return arr;
}