#include <bits/stdc++.h>
#define fi first
#define se second
#define ssize(x) int(x.size())
#define pn printf("\n")
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(), x.rend()
#define vv vector
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
int inf = 2e09; ll infll = 2e18; int mod = 119<<23|1;
ll minimum_walk(vv<int> p, int s){
int n = ssize(p);
vv<int> vis(n, 0);
int l = 0;
ll result = 0;
vv<pii> st;
for(int i = 0; i < n; ++i) if(!vis[i]){
//~ printf("%d\n", i);
int mx = i; vis[i] = ++l; result += abs(i-p[i]);
for(int u = p[i]; u != i; u = p[u]) vis[u] = l, mx = max(mx, u), result += abs(u-p[u]);
if(st.empty()) {if(mx != i) st.emplace_back(i, mx);}
else{
if(i < st.back().se) st.back().se = max(st.back().se, mx);
else if(mx != i) st.emplace_back(i, mx);
}
//~ printf("%d %lld\n", i, result);
}
//~ printf("a\n");
for(int i = 1; i < ssize(st); ++i) result += 2*(st[i].fi-st[i-1].se);
if(ssize(st) && st[0].fi != 0) result += 2*st[0].fi;
return result;
}
#ifdef LOCAL
int main(){
int T = 1;
for(++T; --T; ){
int n, s; scanf("%d%d", &n, &s);
vv<int> p(n);
for(int i = 0; i < n; ++i) scanf("%d", &p[i]);
ll result = minimum_walk(p, s);
printf("%lld\n", result);
}
return 0;
}
#endif
