#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>

using namespace std;

struct node
{
	int w1,w2;
}P[5001];

int n,w,s,pn;
char ch;

int cmp(const void *a,const void *b)
{
	node *aa=(node *)a;
	node *bb=(node *)b;
	return (aa->w2-aa->w1)-(bb->w2-bb->w1);
}

int main()
{
	freopen("magica.in","r",stdin);
	freopen("magica.out","w",stdout);
	
	scanf("%d%d",&n,&w);
	int t,tt;
	for (int i=1;i<=n;i++)
	{
		scanf("%d",&t);
		ch='!';
		scanf("%c",&ch);
		if (ch!=' ') s+=t;
		else
		{
			scanf("%d",&tt);
			if (tt-t<=w) s+=t;
			else P[++pn].w1=t,P[pn].w2=tt;
		}
	}
	qsort(P+1,pn,sizeof(P[0]),cmp);
	
	for (int i=1;i<=pn;i++)
	{
		if (s<w) s+=P[i].w1;
		else s+=P[i].w2-w;
	}
	printf("%d\n",s);
	return 0;
}