#include<bits/stdc++.h>
#define reg register
#define int long long
inline int read(){
    reg int x=0,k=1; reg char ch=getchar();
    while ('0'>ch||ch>'9') (ch=='-')&&(k=-1),ch=getchar();
    while ('0'<=ch&&ch<='9') x=x*10+ch-48,ch=getchar();
    return x*k;
}
inline int min(reg int x,reg int y){return x<y?x:y;}
inline bool cmin(reg int &x,reg int y){return x>y?x=y,1:0;}
const int N=5010,INF=1e18;
int n,m,T,c[N],f[N][2],prea[N],preb[N],posa[N],posb[N],pos[N],tag[N][N][2];
std::vector<int> va,vb;
inline int geta(reg int l,reg int r,reg int x){return x*(r-l)-(prea[r]-prea[l]);}
inline int getb(reg int l,reg int r,reg int x){return x*(r-l)-(preb[r]-preb[l]);}
signed main(){
    n=read(),T=read();
    for (reg int i=1,x;i<=n;i++){
        char str[3];
        scanf("%s",str),x=read();
        if (str[0]=='A') va.push_back(x); else vb.push_back(x);
        c[++m]=x;
    }  
    va.push_back(0),vb.push_back(0);
    std::sort(c+1,c+m+1),m=std::unique(c+1,c+m+1)-c-1;
    std::sort(va.begin(),va.end()),std::sort(vb.begin(),vb.end());
    for (reg int i=1;i<va.size();i++) prea[i]=prea[i-1]+va[i];
    for (reg int i=1;i<vb.size();i++) preb[i]=preb[i-1]+vb[i];
    memset(tag,0x3f,sizeof(tag));
    reg int ans=INF,now=0;
    for (reg int i=1;i<=m;i++){
        reg int pa=0,pb=0,p=0; 
        memset(f,0x3f,sizeof(f));
        for (reg int j=0;j<=n+2;j++){
            while (pa+1<va.size()&&va[pa+1]<=c[i]+j*T) pa++;
            while (pb+1<vb.size()&&vb[pb+1]<=c[i]+j*T) pb++;
            while (p+1<=m&&c[p+1]<=c[i]+j*T) p++;
            posa[j]=pa,posb[j]=pb,pos[j]=p;
        }
        for (reg int j=0;j<vb.size();j++){
            cmin(tag[i][j][0],tag[i-1][j][0]);
            if (j<=posb[1]) cmin(f[0][0],tag[i][j][0]+getb(j,posb[1],c[i]+T));
        }
        for (reg int j=0;j<va.size();j++){
            cmin(tag[i][j][1],tag[i-1][j][1]);
            if (j<=posa[1]) cmin(f[0][1],tag[i][j][1]+geta(j,posa[1],c[i]+T));
        }
        for (reg int j=0;j<=n;j++){
            cmin(f[j][0],getb(0,posb[j+1],c[i]+(j+1)*T));
            cmin(f[j][1],geta(0,posa[j+1],c[i]+(j+1)*T));

            cmin(f[j+1][1],f[j][0]+geta(posa[j],posa[j+2],c[i]+(j+2)*T));
            cmin(f[j+1][0],f[j][1]+getb(posb[j],posb[j+2],c[i]+(j+2)*T));

            cmin(tag[pos[j+1]+1][posb[j]][0],f[j][1]);
            cmin(tag[pos[j+1]+1][posa[j]][1],f[j][0]);
            
            if (c[i]+j*T>=va.back()&&c[i]+(j+1)*T>=vb.back()) cmin(ans,f[j][0]);
            if (c[i]+j*T>=vb.back()&&c[i]+(j+1)*T>=va.back()) cmin(ans,f[j][1]);
        }
    }
    // std::cerr<<"<< "<<f[3][1][1]<<"\n";
    printf("%lld\n",ans);
    return 0;
}