#include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define FOR(I,A,B) for(int I = (A); I < (B); ++I) typedef long long ll; int main(){ int N, M; cin >> N >> M; vector D; int r = 0, l = 0; FOR (i,0,M) { int d; cin >> d; if (d < 0) { l++; D.push_back(d); } else if (d > 0) { r++; D.push_back(d); } else N--; } sort(D.begin(), D.end()); int ans = 10000000; for (int i = 0; i + N - 1 < D.size(); i++) { if(D[i] > 0) { ans = min(ans, D[i+N-1]); } else if(D[i+N-1] < 0) { ans = min(ans, -D[i]); } else { ans = min(ans, 2 * D[i+N-1] + abs(D[i])); ans = min(ans, 2 * abs(D[i]) + D[i+N-1]); } } cout << ans << endl; return 0; }