The song's in the key of B. Whole song is in the order below. I don't speak 
korean, so I'm sorry if the chords aren't placed at the right times. But its very easy to pick up

B: x24442
 F#: 244322
Abm: 466444
  E: 022100

B (x2444x@1)                  F# (244322@1)           Abm (133111@4)                     ENeo (022100@1)gateun saram tto eopseo juwireul dureobwado geujeo georeohdeongeol 
          
eodiseo channi
B (x2444x@1)                      F# (244322@1)                   AbmNeo (133111@4)gatchi joheun saram neo gatchi joheun saram neo gatchi joheun ma eum 
 E (022100@1)                   
neo gatchi joheun seonmul
 B (x2444x@1)                 F# (244322@1)              Abm (133111@4)                   E (022100@1)
Neomu dahaeng iya aesseo neorel jikyeojul geu sarami baro naraseo eodiseo 
   
channi
B (x2444x@1)                    F# (244322@1)                     AbmNa (133111@4)gatchi haengbokhan nom na gatchi haengbokhan nom na gatchi unneun 
          Egeureon (022100@1)choegoro haengbokhan nom

B (x2444x@1)               F# (244322@1)         Abm (133111@4)          ENeoui (022100@1)ttatteuthan geu soni chagapge, chagapge shikeo isseul ttae
 B (x2444x@1)                     F# (244322@1)          Abm (133111@4)        ENeoui (022100@1)ganghaetdeon geu maeumi nal karopge sangcheo badasseul ttae
 B (x2444x@1)                  F# (244322@1)          Abm (133111@4)                        ENaega (022100@1)jaba julge anajulge salmyeoshi, geugeoseuro jakeun iroman dwendamyeon johgesseo
 B (x2444x@1)                 F# (244322@1)               Abm (133111@4)                    EEonjena (022100@1)deo maneun geol haejugo shipeun nae mam neon da mollado dwae
  B (x2444x@1)             F# (244322@1)   Abm (133111@4)            EGaseumi (022100@1)sorichyeo marhae jayuro-un nae yeonghon
        B (x2444x@1)                    F# (244322@1)               Abm (133111@4)             
Eonjena cheo-eumui imaeum euro neoreul saranghae georeo watdeon shiganboda
   Enameun (022100@1)nari deo manha

And so on....