#include <bits/stdc++.h>
using namespace std;
const int nx=2e3+5;
int n, m, k, res, l[nx], r[nx], nxt[2*nx], vs[2*nx], dp[2*nx][nx][2];
vector<pair<int, int>> v={{0, 0}};
vector<int> s;
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin>>n>>m>>k;
for (int i=1; i<=n; i++) cin>>l[i]>>r[i], s.push_back(l[i]), s.push_back(r[i]);
s.push_back(0);
s.push_back(m);
sort(s.begin(), s.end());
for (int i=1; i<=n; i++)
{
auto idx=lower_bound(s.begin(), s.end(), l[i])-s.begin();
nxt[idx]=lower_bound(s.begin(), s.end(), r[i])-s.begin()-1;
}
//for (int i=0; i<s.size(); i++) cout<<"nxt "<<i<<' '<<nxt[i]<<'\n';
for (int i=0; i<s.size()-1; i++)
{
if (vs[i]) continue;
if (nxt[i]==0) res+=s[i+1]-s[i];
else
{
if (nxt[i]==i) v.push_back({s[i+1]-s[i], 1}), v.push_back({0, 0});
else
{
int cur=i;
while (nxt[cur])
{
vs[cur]=1;
v.push_back({s[cur+1]-s[cur], 1});
cur=nxt[cur];
}
vs[cur]=1;
v.push_back({s[cur+1]-s[cur], 0});
}
}
}
//cout<<"res "<<res<<'\n';
for (int i=1; i<v.size(); i++)
{
//cout<<"item "<<v[i].first<<' '<<v[i].second<<'\n';
dp[i][0][0]=v[i].second;
for (int j=1; j<=k; j++)
{
dp[i][j][0]=max(dp[i-1][j-v[i].second][0]+v[i].first, dp[i-1][j-v[i].second][1]);
dp[i][j][1]=max(dp[i-1][j][0], dp[i-1][j][1]);
//cout<<"debug dp "<<i<<' '<<j<<' '<<dp[i][j][0]<<' '<<dp[i][j][1]<<'\n';
}
}
cout<<res+dp[v.size()-1][k][0]<<'\n';
}
/*
2 20 1
4 10
8 15
*/
