#include <bits/stdc++.h> using namespace std; #define int long long void solve() { int n;cin>>n; int arr[n]; for(int i=0;i<n;i++)cin>>arr[i]; int cavab=LLONG_MAX; for(int k=0;k<n;k++){ int a=0,b=0; for(int i=1;i<=k;i++){ if(arr[i]<=arr[i-1])a+=arr[i-1]-arr[i]+1; } for(int i=k;i<n-1;i++){ if(arr[i]<=arr[i+1])b+=arr[i+1]-arr[i]+1; } cavab=min({cavab,max(a,b)}); } cout<<cavab<<"\n"; } signed main() { ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0); solve(); }