process.stdin.resume();
process.stdin.setEncoding('ascii');

var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;

process.stdin.on('data', function (data) {
    input_stdin += data;
});

process.stdin.on('end', function () {
    input_stdin_array = input_stdin.split("\n");
    main();    
});

function readLine() {
    return input_stdin_array[input_currentline++];
}

/////////////// ignore above this line ////////////////////

function main() {
    var n = parseInt(readLine());
    a = readLine().split(' ');
    a = a.map(Number);
    // your code goes here
    
    //first find the distance from 0 for all.
    var firstMin;
    var secondMin;
    var zeroDistance = [];
    if(a[0] > -1) {
        firstMin = {
            value: a[0],
            position: 0
        };
        secondMin = {
            value: a[0],
            position: 0
        };
    } else {
        firstMin = {
            value: (a[0] * -1),
            position: 0
        };   
        secondMin = {
            value: (a[0] * -1),
            position: 0
        };  
    }
    a.forEach(function(number, index) {
        if(number < 0) {
            var n = (number*(-1));
            zeroDistance.push(n);        
        } else {
            zeroDistance.push(number);
        }
        
        if(zeroDistance[index] < firstMin.value) {
            firstMin.value = zeroDistance[index];
            firstMin.position = index;
        }
    });
    
    zeroDistance.forEach(function(number, index) {
        if(number < secondMin.value && index !== firstMin.position) {
            secondMin.value = number;
            secondMin.position = index;
        }
    });
    
    console.log(firstMin.value + secondMin.value);
}