const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;
void async function () {
// Write your code here
while(line = await readline()){
A = await readline();
maxkk(A);
}
function maxkk(A){
As = A.split(' ');
Aint = As.map(Number);
res = new Array;
len = Aint.length;
for(let i=0; i<len-1; i++){
res.push(Aint[i+1]-Aint[i]);
}
let max=0;
for(let i=0; i<res.length; i++){
max=Math.max(max, res[i]);
}
console.log(max);
}
}()