function solve(arr){
    let assocArr = {};

    for(let i = 0; i < arr.length; i++){
        let token = arr[i];
        if(isNaN(token)){
            if(!assocArr.hasOwnProperty(token)){
                assocArr[token] = 0;
            }
        } else{
            assocArr[arr[i-1]] += Number(token);
        }
    }

    Object.keys(assocArr).forEach(key=> {
        console.log(`${key} -> ${assocArr[key]}`);
    });
}