#include <limits> #include <iostream> #include <algorithm> #include <iomanip> #include <map> #include <set> #include <queue> #include <stack> #include <numeric> #include <bitset> #include <cmath> static const int MOD = 1000000007; using ll = long long; using u32 = uint32_t; using namespace std; template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208; int main() { int n, m; cin >> n >> m; vector<ll> x(n), a(n); for (auto &&i : x) scanf("%lld", &i); for (auto &&j : a) scanf("%lld", &j); m--; int l = m, r = m; ll lb = x[m]-a[m], ub = x[m]+a[m]; while((0 < l && lb <= x[l-1]) || (r < n-1 && x[r+1] <= ub)){ if((0 < l && lb <= x[l-1])){ l--; lb = min(lb, x[l]-a[l]); ub = max(ub, x[l]+a[l]); } if((r < n-1 && x[r+1] <= ub)){ r++; lb = min(lb, x[r]-a[r]); ub = max(ub, x[r]+a[r]); } } cout << r-l+1 << "\n"; return 0; }